Method of and means for forming screw caps



0a. 21, 1930. w. J. PEELLE 1,778,960

METHOD OF AND MEANS FOR FORMING SCREW CAPS Filed July 3, 1929 Patented Oct. 21, 1 930 UNITED-STATES PATENT oprica wmis :r. rename, or ammo, rumors, ASSIGNOR 'IO caowir coax AND am comrm, mc.,=or NEW YORK, N. Y., "A com-omnon or NEW Yonx 1 mentor or AND MEANS roa roamne scnnw CAPS" A uoaacn tiled July 3,1929. serial in. 375,619.

Theinvention pertains to the making of screw-caps, and more especially to caps of the type disclosed in my prior Patent No. 1,476,918 dated December 11, 1923, in which the skirt is screw-threaded and has formed therein at circumferentially spaced intervals in the thread, enlargements or protuberances adapted to be flattened out to increase the eflective circumference of the skirt, and thus permitting its easy removal from the container.

The primary object of the present invention is to provide for the practical and economical manufacture of screw-caps of the character set forth. 1

I attain this object by rolling the skirt of the cap between two revolving dies 0 rating to form the screw-threads and protu erances simultaneously, the circumference of the dies being such that for each revolution of the" cap the dies rotate through a distance which is greater than one revolution by the difference between the circumferences of the dies and the cap.

In the accompanying drawings,

' Figure 1 is an elevational view of two 00- ..cting dies operating upon a cap, the latter being shown partially in section.

. Fig. 2 is a view showing the dies in edge elevation with the cap being operated upon shown in section.

Fig. 3 is a viewshowing in perspective the two coacting dies detached.

Fig. 4 is an underside perspective view of a cap formed in accordance with the inven- Fig. '5 is a plan view illustrating one method of mounting the dies.

In th'e illustrative embodiment of the invention, the cap to be formed comprises a main or top wall 7 having a peripheral flange 8 equipped with a rounded thread having a top 9 and a bottom 10 (Figs. 2 and 4). ,At

spaced points throughout the circumference of the cap, interposed'in or interrupting the thread, are a plurality of enlargements or protuberances 11. The latter in the present instance are of a length such as to extend in a direction parallel with the axis of the cap ously shaped blank tween two opposed dies 12 and convolutions of the thread.

In forming the screw-thread together with the enlargements or protuberances, a previaving a plain skirt8 with a beaded peripheral-edge is placed be- 13 suitably mounted upon a machine frame 14. andadapted to be driven in oppositedirections: at uniform speed. Oneof the dies, as for example: thedie 13, may bemounted for movement toward and from the other die through the medium of a sliding head 1-5,the head 16 for the stationary die being fixed. 17 and 18 designate gears'through the medium'of which both dies may be rotated. V

L-The dies 12' and 13 as shown in Fig. 1 are made of equal diameter and have their peripheral surfaces shaped to provide coacting screw-thread-forming ribs and grooves helically disposed (Fig. 2). At equidistantly spaced points inthe peripheryof the die .12

are a plurality of bosses or projections 19aptoms and tops of the screwthread-forming grooves and ribs. Similarly, the die 13 is provided with equi-distantly sp adapted to receivethe pro ections 19. The latter may be formed integrally with the die 12 or may be formed separately and secured an notches 21 formed inthe periphery of the 'ie12.

It will be observed from Figs. 1 and 2 that the dies12 and 13 are of-a diameter somewhat less than that of the cap skirt 8, and the diflerence in circumference is in the present instance equal to the length of'the segmentbetween two adjacent projections 19, or be- --tween two adjacent recesses 20. The result of this arrangement is that the die 12 with its -projections 19 is ada ted to receive freely a blank cap to be formed and upon the com pletion of the forming'operation to permit} the cap to be removed readlly.

I In the forming operation the dies'rotate through a'distance which is greater than'one revolution by the length of the segment between'twoprojections 19 or recesses 20, in 1 order to effect one complete revolution of theaced recesses 20 I cap. Accordingly the portions of the dies,

which form the first protuberance also form the last rotuberance, and the screw-threads formed in the segment between said protuberances are formed by the same portions of the'dies that form the initial portion of the thread. As a result a slight distortion oc- "curs at the end of the thread, or, in other words, a true helical thread isnot formed. In work of this class, however, the-permissible tolerances are so large that the slight distortion occurring is negligible especially when the portion thus distorted is small as compared to the entire circumference of the cap as is the case when a relatively large num-.

v 1. An-apparatus for forming screw-caps comprising a pair ofcircular rotatable dies between which the skirt of the cap" is to be forming portions with spaced coacting projection's and recesses interposed at spaced in- 5. The method of forming a screw-ca for jars and the like which consists in r0 ing the skirt of the cap between two revoluble dies of-equal size and of less diameter than the cap to form simultaneously a screwthread and plurality of protuberances spaced 'apart a distance correspondin to the'excess in the length of the circum erence of the skirt as compared to the circumference of the dies, and limiting the extent of rotation of the dies a roximately to two complete revolutions o t e cap.

In testimony whereof, I have hereunto affixed my signature.

- Y WILLIS J. PEELLE.

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' rolled, said dies having peripheral threadl tervals in the thread-forming'portions, and i u said dies having a circumference which is less than the circumference of the cap by the dis-, tance between two of said projections.

2. An apparatus for. forming screw-capscomprising a pair of circular rotatable dies between which the skirt of'theicap is to be rolled, said dies having peripheral threadforming portions with equally spaced coacting projections and recesses interposed at s aced intervalsin the'thread-forming porioo t1ons," and said dies having a circumference which is less than the circumference of the capby the distance between two adjacent pros I jections. r v y 3. An apparatus for a forming screw-caps comprising a .pair of circular rotatable dies between which the skirt of the ca is to be rolled, said dies having their perip eral surfaces shaped to forma screw-thread in said skirt with spaced enlargements in the thread, and said dies further being of equal size and having a circumference which is less than the circumference of the cap skirt by the distance between two enlargements. I

i 4. The method of forming a screw-ca for jars and the like which consists in ro ling the skirt of thecap between two revoluble dies of equal size andof less diameter than the cap to form, simultaneously a screwthread' and plurality of protuberances spaced apart a distance correspondin to the excess,

in the length of the circum erence of'the .skirt as compared to the circumference of the 

